Conventional systems implement transcoding between different multimedia standards. Transcoding converts an audio or video signal from one format to another format. If a video signal has embedded subtitles, transcoding presents some unique difficulties. In particular, for real time encoding in the context of consumer electronics with limited memory, rate control is a key element of the encoding process. Subtitles have variable duration elements, where traditional audio/video (A/V) applications have fixed duration elements (i.e., audio frames and video field/frames). Conventional standards have some kind of buffer modeling to guarantee decoders with limited memory will be able to decode the bitstream. However, such systems are not compatible between different standards and systems.
It would be desirable to implement a system with rate control and/or real-time transcoding of subtitles in the context of consumer electronics device.